@article{EJDE_2011__2011__a66,
     author = {Zhao, Kaihong and Li, Yongkun},
     title = {Multiple positive periodic solutions to a non-autonomous {Lotka-Volterra} predator-prey system with harvesting terms},
     journal = {Electronic Journal of Differential Equations},
     publisher = {mathdoc},
     volume = {2011},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/EJDE_2011__2011__a66/}
}